EXPRESSION OF THE <i>OSA</i> GENE IN TRANSGENIC PLANTS CONFERS RESISTANCE TO <i>AGROBACTERIUM</i> TRANSFORMATION AND CROWN GALL DISEASE

摘要

When co-resident with the Ti-plasmid of Agrobacterium tumefaciens, the osa gene of the plasmid pSa causes oncogenic suppression of crown gall tumorigenesis by inhibiting transport of VirE2 protein from Agrobacterium to the plant cell. To determine whether transgenic plants expressing osa also are resistant to Agrobacterium-mediated transformation, a Cauliflower Mosaic Virus (CaMV) 35S promoter-osa-intron chimaeric gene was introduced into Arabidopsis thaliana and the resulting T2 and T3 progeny were tested for susceptibility to Agrobacterium transformation, using as assays crown gall tumorigenesis, transformation to phosphinothricin-resistance, and the transient and stable expression of GUS activity. Of the 13 transgenic lines tested, 8 showed some level of resistance to subsequent Agrobacterium transformation; several lines were highly resistant. Resistance to transformation co-segregated with the T-DNA containing the osa transgene. This invention provides commercial use in protecting plants from crown gall disease by transforming them with the osa gene.